(a) Field of the Invention
The present invention relates to a visual inspection apparatus and a method of inspecting a display panel using the visual inspection apparatus.
(b) Description of the Related Art
Flat panel displays (FPD) such as liquid crystal displays, organic light emitting displays, field emission displays (FED), and plasma display panels (PDP) have been developed and are widely used.
Such flat panel displays (FPD) should be subjected to various inspection processes before coming to the market. A variety of defects in a display panel such as short-circuits between lines and particle contamination may occur while manufacturing the same. Accordingly, it is very important in view of manufacturing yield to detect such defects, to repair or discard the defective panels, and to remove causes of the defects.
Among a variety of inspections, a visual inspection for detecting defective pixels and defective lines by the use of an image displayed on the display panel is often used. In the visual inspection, the defects are detected by the use of a visual inspection apparatus or the naked eye of a person. The visual inspection is generally performed when an image can be displayed on the display panel with application of image signals, that is, after the individual panels are manufactured, in the processes of manufacturing a display panel.
During such inspection, an error that a defective display panel is determined to be a normal display panel or a normal display panel is determined to be a defective display panel may occur. If much time is required for the inspection, the overall manufacturing time for one product increases, and the size of the display panel may be different for different products. Accordingly, when various groups of products are manufactured, the inspection process should be optimized for every group of products. As a result, inspection accuracy, high inspection speed, and easy modification of inspection conditions are very important aspects when inspecting a display panel.
Therefore, an inspection apparatus that can perform an inspection process at higher speed, accurately detect defects, and cope with various groups of products is required.